Efficiency of some actinomycete isolates in biological treatment and removal of heavy metals from wastewater

Abstract

The main focus of studies and research in the field of wastewater treatment is treating wastewater without causing environmental hazards as well as getting benefits from the treated waste materials. In this regard, the aim of the current study was to isolate some actinomycete strains from Beni-Suef Wastewater Treatment Plant to study their capacities for biological treatment and for removal of heavy metals from the wastewater. For this purpose, 17 actinomycete strains were isolated from 3 wastewater samples representing the main stages of treatment in the plant, namely: the influent, the secondary sedimentation tank and the effluent. Then, 10 morphologically dissimilar isolates were selected. The 10 selected actinomycete isolates were characterized by their morphological characteristics and were found to belong to the genera Nocardia, Streptomyces, Rhodococcus, Gordonia and Nocardiopsis. The ability of the selected actinomycetes for biological treatment of the wastewater was evaluated by measuring the biochemical oxygen demand (BOD), the chemical oxygen demand (COD) and the total suspended solids (TSS); and their ability for removal of some heavy metals (Cu, Fe, Mn, Pb and Zn) was also determined. The results showed that most of the selected actinomycetes were effective in the biological treatment of the wastewater and have the ability to decrease the values of BOD, COD and TSS; and also to reduce the concentrations of the tested heavy metals (Cu, Fe, Mn, Pb and Zn) markedly. The Streptomyces strain C11 was found to be the most efficient organism in respect to biological treatment of the wastewater and removal of the heavy metals from the raw wastewater.

Key words: Actinomycetes, wastewater, biological treatment, heavy metals removal.